Method for greatly improving recovery ratio of permanently modified non-homogeneous oil reservoir

Abstract

The invention discloses a method for greatly improving the recovery ratio of a permanently modified non-homogeneous oil reservoir. A dynamic balance control principle is put forward. Through continuous "establishing, breaking and re-establishing' of seepage resistance balance, the permeability limit of the oil reservoir is reduced to the maximum extent. A 'driving, adjusting and plugging integration' varied technical system is developed and is characterized in that an injection system is converted from a complete liquid phase to liquid and solid phase coexistence, and the viscosity of a solution becomes smaller to be in concert with the varied oil reservoir, so that the self-adaptive matching with complex rock pores is realized. After polymer flooding, low-permeability part oil which has not been used is harder to use compared with the condition of water flooding, so that the damage to a low-permeability part must be reduced in the oil reservoir non-homogeneous modifying process, adverse factors must be changed to favorable factors, polymer which exerts the displacement effect precipitates out of an injection liquid and becomes a solid phase to block a large pore passage, and meanwhile, liquid turning to the low-permeability part is like water as the precipitation of the polymer, and the damage to the oil reservoir is very small. Through the measures, the recovery efficiency can be theoretically improved by more than 30% on the basis of water flooding.

Description

technical field [0001] This technology is mainly used in the technical field of mining from porous media, such as petroleum development, and is especially suitable for heterogeneous oil reservoirs. Background technique [0002] Regardless of the production method, the degree of heterogeneity of the reservoir is one of the decisive factors affecting the ultimate recovery of the oil field. Generally speaking, the more severe the degree of heterogeneity, the lower the recovery rate. At present, water flooding is the main production method of oil fields in the world, and the recovery rate of water flooding is generally about 30%. ), even after chemical compound flooding, there are still about 50% of the remaining oil remaining in the ground, how to economically and effectively exploit this part of oil is of great significance for extending the production life of old oilfields. [0003] Liu Lu et al. through the "Numerical Simulation Study on the Effect of Permeability Variation...

AI Technical Summary

Problems solved by technology

For the oil phase, it mainly solves the problem of the flow mechanism. For the movable remaining oil, it is necessary to analyze the reason why it cannot be started. By providing power and increasing the temperature to supplement energy, the oil in the porous medium can flow, and the adhesion Retained oil on the rock surface is removed from the rock by washing, bacterial degradation, etc.

For rocks, the problem of flow limitation is mainly solved. For rocks with dense pores, the flow limitation should be lifted, and for large pores, the flow limitation should be implemented for invalid circulation.